NOW NOT STARTING

as I went to work yesterday, I noticed the car drive like it had handbrake on, it seemed like it didnt change through the gears like normal. I stopped to check if it had trans fluid, it did, so I tried moving in reverse then forward, it works. But as I drive, it just lack the performance, seems like it had handbrake on and the trans was struggling. So I just drove it back home and left it there. Didnt want to risk further damage. So the next day went to take it to mechanic, the car was turning over, but not starting now. What could it be gentlemen?